1. Field of the Invention
The present invention relates to a sheet conveying apparatus for delivering upright sheets of paper to paths of different levels.
2. Description of the Related Art
There is known a sheet conveying apparatus for delivering, into stackers corresponding to addresses, postal items from which data expressed as postal codes and indicating the addresses has already been read. OCR/VSC integrated systems incorporating the conveying apparatus generally need several tens or more of stackers for delivering postal items. To this end, in the OCR/VSC integrated systems, a large number of stackers are stacked in several stages.
More specifically, a conveyor apparatus for use in general OCR/VSC integrated systems is designed to deliver postal items having their address information already read to paths of different levels, and then into designated stackers in each stage. When delivering postal items to paths of different levels, it is technically difficult to deliver upright postal items with their attitudes unchanged. Therefore, in general, postal items conveyed flat are delivered to paths of different levels.
Jpn. Pat. Appln. KOKAI Publication No. 9-155297, for example, discloses a conveyor apparatus for OCR/VSC integrated systems, in which postal items are delivered flat to a plurality of paths of different levels with their conveyance attitude unchanged, and then are twisted through 90° into an upright attitude and collected into stackers.
If postal items are horizontally stacked on each other in each stacker, operators may well cause the postal items to fall apart to pieces when they-remove them from each stacker. To avoid this, in the disclosed apparatus, the postal items are conveyed flat, and are brought upright when they are collected into each stacker, which facilitates removal by operators.
However, in the above-described apparatus, postal items delivered flat to paths of different levels are abruptly rotated through 90° over a relatively short distance. Therefore, the conveyance attitude of each postal item is liable to be off balance. Where postal items are twisted while being conveyed by a pair of conveyor belts, if, in particular, they are heavy, a great centrifugal force will be exerted on them when their attitude is changed from flat to upright. As a result, the postal items may well be ejected from between the two conveyor belts.